EP 0799672 A1 19971008 - Ball screw drive with dynamically adjustable preload
Title (en)
Ball screw drive with dynamically adjustable preload
Title (de)
Kugelgewindetrieb mit dynamisch einstellbarer Vorspannung
Title (fr)
Vis à billes avec précontrainte ajustable dynamiquement
Publication
Application
Priority
US 62627396 A 19960404
Abstract (en)
An improved ball screw drive mechanism and associated method and system for controlling linear and position motion of a movably mounted carriage carrying an operative machine tool working element along a line of action within said machine tool. A threaded ball screw is stationarily non-rotatably mounted in the machine tool to extend parallel to the line of action traversed by the carriage. A pair of threaded ball nuts are laterally restrained in and mounted for free rotation thereof in a drive mechanism of the carriage and threadably and concentrically engage the ball screw in laterally spaced apart co-axial relationship therealong. A pair of digitally controlled electric drive motors are mounted in the carriage and individually operably coupled by their rotors to the ball nuts for individually imparting rotational torque to the nuts. A conventional programmably CNC controller having single axis and slave dual motor control capability, or two axis dual motor control capability, is programmed to synchronously control both motors for causing the ball nuts to conjointly produce computer controlled linear motion and positioning of the carriage along the stationary ball screw, and to develop anti-backlash preload forces between the ball nuts relative to the ball screw. The system can also produce an electromotive and/or frictional braking force for decelerating and/or holding the carriage in a selected stationarily fixed position along the line of action. The two motor rotors can exert rotational torque on the ball nuts in opposite rotary directions with the carriage moving and/or stationary. Preload forces exerted between the ball nut can be dynamically adjusted by monitoring the load and/or position of each of the motor rotors and adjusting the power input thereto individually while producing conjoint rotary motion of the motors to drive the carriage along the ball screw. The angular phase relationship between the motor rotors and hence between the ball nuts can be controlled to vary variably the spread distance between the nuts axially of the screw within the range of system screw-to-nut backlash clearance as a function of carriage travel position and/or mode of machine tool operation. <IMAGE>
IPC 1-7
IPC 8 full level
B23Q 5/40 (2006.01); B23Q 5/56 (2006.01); F16H 25/20 (2006.01); H02K 7/06 (2006.01)
CPC (source: EP US)
B23Q 5/408 (2013.01 - EP US); B23Q 5/56 (2013.01 - EP US); F16H 25/2006 (2013.01 - EP US); H02K 7/06 (2013.01 - EP US); Y10T 74/18632 (2015.01 - EP US); Y10T 74/19902 (2015.01 - EP US)
Citation (search report)
- [A] GB 2116460 A 19830928 - KEARNEY & TRECKER CORP
- [A] DE 3938353 A1 19900523 - FISW GMBH [DE]
- [A] WO 8302142 A1 19830623 - KEARNEY & TRECKER CORP [US]
- [A] GB 891036 A 19620307 - GEN ELECTRIC CO LTD
- [A] CH 586583 A5 19770415 - FEHR MAX
- [A] FR 2355215 A1 19780113 - PAINI MORINI AMADORI SPA [IT]
- [A] US 5327795 A 19940712 - KATAHIRA MASAYUKI [JP]
- [A] PATENT ABSTRACTS OF JAPAN vol. 12, no. 78 (M - 675) 11 March 1988 (1988-03-11)
Designated contracting state (EPC)
DE ES FR GB SE
DOCDB simple family (publication)
EP 0799672 A1 19971008; CA 2201659 A1 19971004; MX 9702443 A 19980531; US 5704250 A 19980106
DOCDB simple family (application)
EP 97302208 A 19970401; CA 2201659 A 19970403; MX 9702443 A 19970403; US 62627396 A 19960404